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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /nsprpub/lib/ds/plarena.c | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'nsprpub/lib/ds/plarena.c')
-rw-r--r-- | nsprpub/lib/ds/plarena.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/nsprpub/lib/ds/plarena.c b/nsprpub/lib/ds/plarena.c new file mode 100644 index 000000000..a582ac638 --- /dev/null +++ b/nsprpub/lib/ds/plarena.c @@ -0,0 +1,334 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * Lifetime-based fast allocation, inspired by much prior art, including + * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes" + * David R. Hanson, Software -- Practice and Experience, Vol. 20(1). + */ +#include <stdlib.h> +#include <string.h> +#include "plarena.h" +#include "prmem.h" +#include "prbit.h" +#include "prlog.h" +#include "prlock.h" +#include "prinit.h" + +#ifdef PL_ARENAMETER +static PLArenaStats *arena_stats_list; + +#define COUNT(pool,what) (pool)->stats.what++ +#else +#define COUNT(pool,what) /* nothing */ +#endif + +#define PL_ARENA_DEFAULT_ALIGN sizeof(double) + +PR_IMPLEMENT(void) PL_InitArenaPool( + PLArenaPool *pool, const char *name, PRUint32 size, PRUint32 align) +{ + /* + * Look-up table of PR_BITMASK(PR_CeilingLog2(align)) values for + * align = 1 to 32. + */ + static const PRUint8 pmasks[33] = { + 0, /* not used */ + 0, 1, 3, 3, 7, 7, 7, 7,15,15,15,15,15,15,15,15, /* 1 ... 16 */ + 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31}; /* 17 ... 32 */ + + if (align == 0) + align = PL_ARENA_DEFAULT_ALIGN; + + if (align < sizeof(pmasks)/sizeof(pmasks[0])) + pool->mask = pmasks[align]; + else + pool->mask = PR_BITMASK(PR_CeilingLog2(align)); + + pool->first.next = NULL; + /* Set all three addresses in pool->first to the same dummy value. + * These addresses are only compared with each other, but never + * dereferenced. */ + pool->first.base = pool->first.avail = pool->first.limit = + (PRUword)PL_ARENA_ALIGN(pool, &pool->first + 1); + pool->current = &pool->first; + /* + * Compute the net size so that each arena's gross size is |size|. + * sizeof(PLArena) + pool->mask is the header and alignment slop + * that PL_ArenaAllocate adds to the net size. + */ + if (size > sizeof(PLArena) + pool->mask) + pool->arenasize = size - (sizeof(PLArena) + pool->mask); + else + pool->arenasize = size; +#ifdef PL_ARENAMETER + memset(&pool->stats, 0, sizeof pool->stats); + pool->stats.name = strdup(name); + pool->stats.next = arena_stats_list; + arena_stats_list = &pool->stats; +#endif +} + + +/* +** PL_ArenaAllocate() -- allocate space from an arena pool +** +** Description: PL_ArenaAllocate() allocates space from an arena +** pool. +** +** First, try to satisfy the request from arenas starting at +** pool->current. Then try to allocate a new arena from the heap. +** +** Returns: pointer to allocated space or NULL +** +** Notes: The original implementation had some difficult to +** solve bugs; the code was difficult to read. Sometimes it's +** just easier to rewrite it. I did that. larryh. +** +** See also: bugzilla: 45343. +** +*/ + +PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb) +{ + PLArena *a; + char *rp; /* returned pointer */ + PRUint32 nbOld; + + PR_ASSERT((nb & pool->mask) == 0); + + nbOld = nb; + nb = (PRUword)PL_ARENA_ALIGN(pool, nb); /* force alignment */ + if (nb < nbOld) + return NULL; + + /* attempt to allocate from arenas at pool->current */ + { + a = pool->current; + do { + if ( nb <= a->limit - a->avail ) { + pool->current = a; + rp = (char *)a->avail; + a->avail += nb; + return rp; + } + } while( NULL != (a = a->next) ); + } + + /* attempt to allocate from the heap */ + { + PRUint32 sz = PR_MAX(pool->arenasize, nb); + if (PR_UINT32_MAX - sz < sizeof *a + pool->mask) { + a = NULL; + } else { + sz += sizeof *a + pool->mask; /* header and alignment slop */ + a = (PLArena*)PR_MALLOC(sz); + } + if ( NULL != a ) { + a->limit = (PRUword)a + sz; + a->base = a->avail = (PRUword)PL_ARENA_ALIGN(pool, a + 1); + PL_MAKE_MEM_NOACCESS((void*)a->avail, a->limit - a->avail); + rp = (char *)a->avail; + a->avail += nb; + PR_ASSERT(a->avail <= a->limit); + /* the newly allocated arena is linked after pool->current + * and becomes pool->current */ + a->next = pool->current->next; + pool->current->next = a; + pool->current = a; + if ( NULL == pool->first.next ) + pool->first.next = a; + PL_COUNT_ARENA(pool,++); + COUNT(pool, nmallocs); + return(rp); + } + } + + /* we got to here, and there's no memory to allocate */ + return(NULL); +} /* --- end PL_ArenaAllocate() --- */ + +PR_IMPLEMENT(void *) PL_ArenaGrow( + PLArenaPool *pool, void *p, PRUint32 size, PRUint32 incr) +{ + void *newp; + + if (PR_UINT32_MAX - size < incr) + return NULL; + PL_ARENA_ALLOCATE(newp, pool, size + incr); + if (newp) + memcpy(newp, p, size); + return newp; +} + +PR_IMPLEMENT(void) PL_ClearArenaPool(PLArenaPool *pool, PRInt32 pattern) +{ + PLArena *a; + + for (a = pool->first.next; a; a = a->next) { + PR_ASSERT(a->base <= a->avail && a->avail <= a->limit); + a->avail = a->base; + PL_CLEAR_UNUSED_PATTERN(a, pattern); + PL_MAKE_MEM_NOACCESS((void*)a->avail, a->limit - a->avail); + } +} + +/* + * Free tail arenas linked after head, which may not be the true list head. + * Reset pool->current to point to head in case it pointed at a tail arena. + */ +static void FreeArenaList(PLArenaPool *pool, PLArena *head) +{ + PLArena *a = head->next; + if (!a) + return; + + head->next = NULL; + + do { + PLArena *tmp = a; + a = a->next; + PL_CLEAR_ARENA(tmp); + PL_COUNT_ARENA(pool,--); + PR_DELETE(tmp); + } while (a); + + pool->current = head; +} + +PR_IMPLEMENT(void) PL_ArenaRelease(PLArenaPool *pool, char *mark) +{ + PLArena *a; + + for (a = &pool->first; a; a = a->next) { + if (PR_UPTRDIFF(mark, a->base) <= PR_UPTRDIFF(a->avail, a->base)) { + a->avail = (PRUword)PL_ARENA_ALIGN(pool, mark); + FreeArenaList(pool, a); + return; + } + } +} + +PR_IMPLEMENT(void) PL_FreeArenaPool(PLArenaPool *pool) +{ + FreeArenaList(pool, &pool->first); + COUNT(pool, ndeallocs); +} + +PR_IMPLEMENT(void) PL_FinishArenaPool(PLArenaPool *pool) +{ + FreeArenaList(pool, &pool->first); +#ifdef PL_ARENAMETER + { + PLArenaStats *stats, **statsp; + + if (pool->stats.name) + PR_DELETE(pool->stats.name); + for (statsp = &arena_stats_list; (stats = *statsp) != 0; + statsp = &stats->next) { + if (stats == &pool->stats) { + *statsp = stats->next; + return; + } + } + } +#endif +} + +PR_IMPLEMENT(void) PL_CompactArenaPool(PLArenaPool *ap) +{ +} + +PR_IMPLEMENT(void) PL_ArenaFinish(void) +{ +} + +PR_IMPLEMENT(size_t) PL_SizeOfArenaPoolExcludingPool( + const PLArenaPool *pool, PLMallocSizeFn mallocSizeOf) +{ + /* + * The first PLArena is within |pool|, so don't measure it. Subsequent + * PLArenas are separate and must be measured. + */ + size_t size = 0; + const PLArena *arena = pool->first.next; + while (arena) { + size += mallocSizeOf(arena); + arena = arena->next; + } + return size; +} + +#ifdef PL_ARENAMETER +PR_IMPLEMENT(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb) +{ + pool->stats.nallocs++; + pool->stats.nbytes += nb; + if (nb > pool->stats.maxalloc) + pool->stats.maxalloc = nb; + pool->stats.variance += nb * nb; +} + +PR_IMPLEMENT(void) PL_ArenaCountInplaceGrowth( + PLArenaPool *pool, PRUint32 size, PRUint32 incr) +{ + pool->stats.ninplace++; +} + +PR_IMPLEMENT(void) PL_ArenaCountGrowth( + PLArenaPool *pool, PRUint32 size, PRUint32 incr) +{ + pool->stats.ngrows++; + pool->stats.nbytes += incr; + pool->stats.variance -= size * size; + size += incr; + if (size > pool->stats.maxalloc) + pool->stats.maxalloc = size; + pool->stats.variance += size * size; +} + +PR_IMPLEMENT(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark) +{ + pool->stats.nreleases++; +} + +PR_IMPLEMENT(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark) +{ + pool->stats.nfastrels++; +} + +#include <math.h> +#include <stdio.h> + +PR_IMPLEMENT(void) PL_DumpArenaStats(FILE *fp) +{ + PLArenaStats *stats; + double mean, variance; + + for (stats = arena_stats_list; stats; stats = stats->next) { + if (stats->nallocs != 0) { + mean = (double)stats->nbytes / stats->nallocs; + variance = fabs(stats->variance / stats->nallocs - mean * mean); + } else { + mean = variance = 0; + } + + fprintf(fp, "\n%s allocation statistics:\n", stats->name); + fprintf(fp, " number of arenas: %u\n", stats->narenas); + fprintf(fp, " number of allocations: %u\n", stats->nallocs); + fprintf(fp, " number of free arena reclaims: %u\n", stats->nreclaims); + fprintf(fp, " number of malloc calls: %u\n", stats->nmallocs); + fprintf(fp, " number of deallocations: %u\n", stats->ndeallocs); + fprintf(fp, " number of allocation growths: %u\n", stats->ngrows); + fprintf(fp, " number of in-place growths: %u\n", stats->ninplace); + fprintf(fp, "number of released allocations: %u\n", stats->nreleases); + fprintf(fp, " number of fast releases: %u\n", stats->nfastrels); + fprintf(fp, " total bytes allocated: %u\n", stats->nbytes); + fprintf(fp, " mean allocation size: %g\n", mean); + fprintf(fp, " standard deviation: %g\n", sqrt(variance)); + fprintf(fp, " maximum allocation size: %u\n", stats->maxalloc); + } +} +#endif /* PL_ARENAMETER */ |